I had a similar requirement a while back, though my difference is that I didn't care how big the cache got - nothing could get deleted. So there's no LRU algorithm - once I set something, I don't want it gone until I tell you to get it gone. And thus Cache::Repository. If you add LRU to it (with, say, a size of '0' meaning 'unlimited'), send the patches back :-) Of course, it may be too far off what you need to bother with, but it's at least something to look at.